8.—Tobacco dust:—This article varies greatly. Most sorts are next to worthless, but a few of the brands especially prepared for this work (and sold usually at $3 per hundred pounds, which will last two ordinary home gardens a whole season) are very convenient to use, and effective. Apply with a duster, like that described in Implements.
9.—Carbolic acid emulsion:—1 pint crude acid, 1 lb. soap and 1 gal. water. Dissolve the soap in hot water, add balance of water and pump into an emulsion, as described for kerosene emulsion.
10.—Corrosive sublimate is used to destroy scab on potatoes for seed by dissolving 1 oz. in 7 gals, of water. The same result is obtained by soaking for thirty minutes in a solution of commercial formalin, at the rate of 1 gill to 15 gals. of water.
11.—Bordeaux mixture:—See Chapter XVII.
POISONOUS REMEDIES
12.—Paris green:—This is the standard remedy for eating-bugs and worms. With a modern dusting machine it can be put on dry, early in the morning when the dew is still on. Sometimes it is mixed with plaster. For tender plants easily burned by the pure powder, and where dusting is not convenient, it is mixed with water at the rate of 1 lb. to 50 to 100 gals. and used as a spray. In mixing, make a paste of equal quantities of the powder and quicklime, and then mix thoroughly in the water. It must be kept stirred up when using.
13.—Arsenate of lead:—This has two advantages over Paris green: It will not burn the foliage and it will stay on several times as long. Use from 4 to 10 lbs. in 100 gals. of water; mix well and strain before putting in sprayer. See also Chapter XVII.
14.—Hellebore:—A dry, white powder, used in place of Nos. 12 or 13 on vegetables or fruit that is soon to be eaten. For dusting, use 1 lb. hellebore to 5 of plaster or flour. For watering or spraying, at rate of 1 lb. to 12 gals. of water.
PRECAUTIONS
So much for what we can do in actual hand-to-hand, or rather hand-to- mouth, conflict with the enemy. Very few remedies have ever proved entirely successful, especially on crops covering any considerable area. It will be far better, far easier and far more effective to use the following means of precaution against plant pest ravages: First, aim to have soil, food and plants that will produce a rapid, robust growth without check. Such plants are seldom attacked by any plant disease, and the foliage does not seem to be so tempting to eating- insects; besides which, of course, the plants are much better able to withstand their attack if they do come. Second, give clean, frequent culture and keep the soil busy. Do not have old weeds and refuse lying around for insects and eggs to be sheltered by. Burn all leaves, stems and other refuse from plants that have been diseased. Do not let the ground lie idle, but by continuous cropping keep the bugs, caterpillars and eggs constantly rooted out and exposed to their natural enemies. Third, practice crop rotation. This is of special importance where any root disease is developed. Fourth, watch closely and constantly for the first appearance of trouble. The old adages "eternal vigilance is the price of peace," and "a stitch in time saves nine," are nowhere more applicable than to this matter. And last, and of extreme importance, be prepared to act at once. Do not give the enemy an hour's rest after his presence is discovered. In almost every case it is only by having time to multiply, that damage amounting to anything will be done.